At a time when senators running for president have faced criticism for missing votes, the anti-Washington, anti-leadership Ted Cruz has been quietly productive in at least one quantifiable way: Convening subcommittee hearings.

The Texas Republican — who has the third lowest vote participation percentage in the Senate, according to CQ Vote Watch — has convened nine hearings as chairman of two subcommittees, outpacing the three other senators running for the Republican presidential nomination. “We’re facing enormous challenges in America," Cruz said in an interview last week. "And as chairman of two subcommittees, I have endeavored to convene hearings addressing those challenges. I made a promise to 27 million Texans that if they elected me I would fight for them each and every day. And that is a promise I take very seriously."

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While Cruz has gaveled in the most subcommittee hearings of the four Republican presidential candidates, Sen. Marco Rubio, R-Fla., who has received the most criticism for missing votes, is not far behind with eight. Rubio's vote participation is 65.7 percent vs. 76.3 percent for Cruz.

Commerce Chairman John Thune, R-S.D., under whom both Cruz and Rubio head subcommittees, said that neither attend many full committee hearings, but both are there for hearings on topics of interest and have heavily involved staffs.

He noted that since "everybody’s running as an outsider," in some ways "the less time they’re here, the more they can use that to their advantage."

Cruz's subcommittee activity differs some from his public persona — the man who rails against the "Washington cartel," who called Majority Leader Mitch McConnell, R-Ky., a liar and who was recently deemed "done for" in the Senate by his presidential rival, Sen. Rand Paul of Kentucky.

Cruz wouldn't say if Paul was right that a lack of personal relationships was hurting him in the Senate; he simply said he considers Paul a friend. And he didn't play ball when asked if he would run for a second Senate term if he fails to win the White House.

But some outside observers say he lacks some of the crucial elements of a productive senator. According to James Thurber, a distinguished professor in the Department of Government at American University, participation is only one way to gauge a senator's job performance.

Other qualities include: being supportive of the institution, taking seriously the oversight responsibility, legislating with members of both parties, representing local interests as well as national interests, and doing a good job of educating themselves on their issues and responsibilities.

"He doesn't seem to be an institution builder or supporter," Thurber said. "He's running against the institution. I don't think that's a good senator at all. He's been elected to represent the people of Texas, but in an institution that he has to work within. And he seems to be fighting the institution, acting like an outsider even though he's a member of the Senate."

In response, Cruz spokesman Phil Novack said Cruz wasn’t elected by senators or anyone within D.C., noting Cruz ran for Senate on a platform of preserving and protecting individual liberties, religious liberty and fighting government intrusion.

"That’s why he was elected," Novack said. "It’s because he has demonstrated that he is not afraid to take on Washington, and that he will fight against the Washington cartel of big business and lobbyists who get in bed with career politicians to do nothing but grow government."

As a chairman, it is Cruz's prerogative to decide his subcommittee's priorities. Cruz said he believes "hearings and oversight are a powerful way to focus public attention and scrutiny on issues that matter."

Democratic Sen. Chris Coons of Delaware, a ranking member on the Judiciary Subcommittee on Oversight, Agency Action, Federal Rights and Federal Courts, said Cruz's hearings often seem designed to "highlight partisan differences."

But Coons said he was "encouraged" by a hearing last week that focused on American victims of Palestinian and Iranian terror attacks — a hearing that was also often critical of the Obama administration — and said he respects Cruz for continuing to hold hearings "even in the midst of a very competitive presidential campaign."

"At times, the topics that he chooses, the focus of the hearings and the way he proceeds strikes me as fairly sharp and partisan," the Delaware Democrat said. "But, I was significantly encouraged [last week] that we were able to have a constructive and positive hearing on a difficult and potentially emotional topic."

Coons said he'd like to see "some constructive legislation" come out of the hearings.

When asked if he was finding common ground with Coons, Cruz said he hopes so.

"I’m interested in fixing these problems," Cruz said, "So if there are areas of cooperation, I’m eager to pursue them."